The present disclosure relates to a spindle motor and a hard disk drive (HDD) including the same.
In an information recording and reproducing device such as a HDD for a server, or the like, a fixed shaft-type spindle motor in which a shaft having excellent vibration characteristics is fixed to a case of the hard disk drive is commonly used.
That is, in such a fixed shaft-type spindle motor, the shaft is fixedly installed in the spindle motor mounted in the hard disk drive for a server, in order to prevent a disk from being damaged and not allowing information to be recorded thereon or for information recorded thereon from being read, due to a rotor having a large amplitude, caused by external vibrations.
As described above, in the case in which the fixed-type shaft is installed, thrust members are fixedly installed on upper and lower portions of the shaft.
However, in the case in which the shaft is fixed to the lower thrust member and the lower thrust member is fixed to a base, since the shaft serving as a rotational axis should be firmly fixed in place, a thickness of the lower thrust member is increased and the lower thrust member having the increased thickness is fixed to an outer peripheral surface of the shaft by a method such as a press-fitting method, a bonding method, a sliding coupling method, or the like. Alternatively, the lower thrust member and the shaft are formed integrally with each other.
Particularly, since the lower thrust member has a cup shape which includes a disk part and an extension part protruding from the disk part in an axial direction, it may be difficult to process the lower thrust member so that the disk part and the extension part form an accurate right angle with respect to each other at a boundary portion therebetween. Therefore, contact between a sleeve and the boundary portion between the disk part and the extension part may be generated. Accordingly, a thrust bearing to be formed between the sleeve and the disk part may not be appropriately operated.
Further, the lower thrust member may include a fitting protrusion formed in a central portion thereof and protruding upwardly in the axial direction so as to be coupled to the shaft. In this case, it is also difficult to process the lower thrust member so that the disk part and the fitting protrusion accurately form a right angle with respect to each other at a boundary portion therebetween. Therefore, the shaft may not be completely fitted into the fitting protrusion, thereby hindering thinning of the spindle motor.
As described above, in the spindle motor according to the related art, the thinning of the spindle motor is hindered by a structure of the lower thrust member, a bearing span distance can is inevitably decreased, and the thrust bearing may not be appropriately operated, such that performance of the spindle motor may be impaired.